feat: upgrade to ship Keycloak v22

[Ben-Sheppard]

Which problem does the PR fix?

Closes #849

What's in this PR?

This PR contains a couple of smaller changes (and one larger one!), these are:

1. Upgrade the base Keycloak chart to one that supports Keycloak 22.0.1 (in prep for 8.3)
2. Updates the defaulted Keycloak version from 19.0.3 -> 22.0.1
3. Sets the keycloak.proxy value to edge (this is required to allow the Keycloak UI to load

I have tested this locally the best I can, these tests cover mainly:

1. I can deploy a clean cluster with Keycloak 22, access applications, and deploy a model
2. I can upgrade a cluster from Keycloak 19 -> 22, access applications (no model deployment testing here)

Checklist

Please make sure to follow our Contributing Guide.

Before opening the PR:

• There is no other open pull request for the same update/change.
• The commits follow our Commit Guidelines.
• The main Helm chart and sub-chart are updated (if needed).
• In-repo documentation are updated (if needed).

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• Did all checks/tests pass in the PR?

[aabouzaid]

@Ben-Sheppard thanks for the PR 🙇
I will take a look at it soon.
but now I will just change this to a draft since it has a breaking change that will not be merged before 8.3 (to avoid accidental merge).